Method, base station, and user equipment for implementing carrier aggregation

ABSTRACT

Embodiments of the present invention provide a method, a base station, and a user equipment for implementing carrier aggregation. The method includes: determining, by a primary base station, to add a cell for a user equipment UE; and sending, by the primary base station, a first message to the UE, where the first message is used to instruct the UE to add the cell, the first message includes configuration information of the cell and an identifier or index of a base station to which the cell belongs, and the base station to which the cell belongs is a secondary base station. In the embodiments of the present invention, under the control of the primary base station of the UE, a cell of another base station can be added for the UE, so as to implement carrier aggregation between base stations, thereby further increasing user throughput of the UE.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/288,086, filed on May 27, 2014, which a continuation of InternationalPatent Application No. PCT/CN2012/084811, filed on Nov. 19, 2012, whichclaims priority to Chinese Patent Application No. 201110380488.1, filedon Nov. 25, 2011. All of the afore-mentioned patent applications arehereby incorporated by reference in their entireties.

TECHNICAL FIELD

Embodiments of the present invention relate to the field ofcommunications technologies, and in particular, to a method, a basestation, and a user equipment for implementing carrier aggregation.

BACKGROUND

With the development of mobile communications systems, the quality ofservice that can be provided by a system is increasingly higher. Inorder to maintain the long-term competitive edge of 3GPP, LTE-A(LTE-Advanced, a further evolution of LTE) standards are being set. Inorder to improve the spectral efficiency of the system and thethroughput of a user equipment (User Equipment, UE), carrier aggregation(CA, Carrier Aggregation) is introduced to the LTE-A. The carrieraggregation refers to that the UE can use multiple component carriers(CC, Component Carrier) at the same time to perform uplink and downlinkcommunications, so as to support high-speed data transmission.

The Release-10 version of the 3GPP supports cell (cell) aggregation (orcarrier aggregation) in a base station, and adopts an underlyingaggregation solution, that is, data of a service or a radio bearer(Radio Bearer, RB) may be delivered in multiple cells of the basestation. Specifically, a scheduling program of the base station decidesin real time in which cell a packet of data of a service is delivered,for example, a previous packet of data is delivered in one cell, and anext packet of data may be delivered in another cell.

However, the foregoing version does not yet support cell aggregationbetween base stations; as a result, the throughput of a user equipmentcannot be further increased.

SUMMARY

Embodiments of the present invention provide a method, a base station,and a user equipment for implementing carrier aggregation, which canincrease the throughput of the user equipment.

In one aspect, a method for implementing carrier aggregation isprovided, which includes: determining, by a primary base station, to adda cell for a user equipment UE; and sending, by the primary basestation, a first message to the UE, where the first message is used toinstruct the UE to add the cell, the first message includesconfiguration information of the cell and an identifier or index of abase station to which the cell belongs, and the base station to whichthe cell belongs is a secondary base station.

In another aspect, a method for implementing carrier aggregation isprovided, which includes: receiving, by a secondary base station, asecond message from a primary base station, where the second message isused to request the secondary base station to add a cell of thesecondary base station for a user equipment UE, and the second messageincludes an identifier of the cell of the secondary base station; andadding, by the secondary base station, the cell of the secondary basestation for the UE according to the second message.

In another aspect, a method for implementing carrier aggregation isprovided, which includes: receiving, by a user equipment UE, a firstmessage from a primary base station, where the first message is used toinstruct the UE to add a cell, the first message includes configurationinformation of the cell and an identifier or index of a base station towhich the cell belongs, and the base station to which the cell belongsis a secondary base station; and adding, by the UE, the cell accordingto the first message.

In another aspect, a base station is provided, which includes: adetermining module, configured to determine to add a cell for a userequipment UE; and a sending module, configured to send a first messageto the UE, where the first message is used to instruct the UE to add thecell, the first message includes configuration information of the celland an identifier or index of a base station to which the cell belongs,and the base station to which the cell belongs is a secondary basestation.

In another aspect, a base station is provided, which includes: areceiving module, configured to receive a second message from a primarybase station, where the second message is used to request the basestation to add a cell of the base station for a user equipment UE, andthe second message includes an identifier of the cell of the basestation; and an addition module, configured to add the cell of the basestation for the UE according to the second message.

In another aspect, a UE is provided, which includes: a receiving module,configured to receive a first message from a primary base station, wherethe first message is used to instruct the UE to add a cell, the firstmessage includes configuration information of the cell and an identifieror index of a base station to which the cell belongs, and the basestation to which the cell belongs is a secondary base station; and anaddition module, configured to add a cell of the secondary base stationaccording to the first message.

In another aspect, a communication system is provided, which includesthe base station described above and the UE described above.

In the foregoing technical solutions, under the control of the primarybase station of the UE, a cell of another base station can be added forthe UE, so as to implement carrier aggregation between base stations,thereby further increasing the user throughput of the UE.

BRIEF DESCRIPTION OF DRAWINGS

To illustrate the technical solutions in the embodiments of the presentinvention more clearly, accompanying diagrams required for describingthe embodiments or the prior art are introduced briefly in thefollowing. Apparently, the accompanying diagrams in the followingdescription merely show some embodiments of the present invention, andpersons of ordinary skill in the art may further derive other drawingsfrom these accompanying diagrams without creative efforts.

FIG. 1 is a schematic flowchart of a method for implementing carrieraggregation according to an embodiment of the present invention;

FIG. 2 is a schematic flowchart of a method for implementing carrieraggregation according to another embodiment of the present invention;

FIG. 3 is a schematic flowchart of a method for implementing carrieraggregation according to another embodiment of the present invention;

FIG. 4 is a schematic flowchart of a method for implementing carrieraggregation according to another embodiment of the present invention;

FIG. 5 is a schematic flowchart of a method for implementing carrieraggregation according to another embodiment of the present invention;

FIG. 6 is a schematic flowchart of a method for implementing carrieraggregation according to another embodiment of the present invention;

FIG. 7 is a schematic flowchart of a process of implementing carrieraggregation according to an embodiment of the present invention;

FIG. 8 is a schematic flowchart of a process of implementing carrieraggregation according to another embodiment of the present invention;

FIG. 9 is a schematic flowchart of a process of implementing carrieraggregation according to another embodiment of the present invention;

FIG. 10 is a schematic flowchart of a process of implementing carrieraggregation according to another embodiment of the present invention;

FIG. 11 is a schematic structural diagram of a base station according toan embodiment of the present invention;

FIG. 12 is a schematic structural diagram of a base station according toanother embodiment of the present invention;

FIG. 13 is a schematic structural diagram of a base station according toanother embodiment of the present invention;

FIG. 14 is a schematic structural diagram of a base station according toanother embodiment of the present invention;

FIG. 15 is a schematic structural diagram of a UE according to anembodiment of the present invention;

FIG. 16 is a schematic structural diagram of a UE according to anotherembodiment of the present invention; and

FIG. 17 is a schematic architecture diagram of a system according to anembodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

The following clearly and completely describes the technical solutionsin the embodiments of the present invention with reference to theaccompanying drawings in the embodiments of the present invention.Apparently, the described embodiments are merely a part of theembodiments of the present invention rather than all of the embodiments.All other embodiments obtained by persons of ordinary skill in the artbased on the embodiments of the present invention without creativeefforts shall fall within the protection scope of the present invention.

The technical solutions of the present invention can be applied invarious communications systems, for example, a global system for mobilecommunications (GSM) system, a code division multiple access (CDMA, CodeDivision Multiple Access) system, wideband code division multiple access(WCDMA, Wideband Code Division Multiple Access), a general packet radioservice (GPRS, General Packet Radio Service), long term evolution (LTE,Long Term Evolution), and an advanced long term evolution (LTE-A,Advanced Long Term Evolution) system.

A user equipment (UE, User Equipment) may be called a mobile terminal(Mobile Terminal), a mobile user equipment, and so on, and maycommunicate with one or more core networks through a radio accessnetwork (RAN, Radio Access Network). The user equipment may be a mobileterminal such as a mobile phone (or called a “cellular” phone) and acomputer having a communication function, for example, may be aportable, a pocket-sized, a handheld, a computer built-in, or avehicle-mounted mobile apparatus, which exchange language and/or datawith the radio access network.

A base station may be a base transceiver station (BTS, Base TransceiverStation) in the GSM or CDMA, may also be a base station (NodeB) in theWCDMA, or may also be an evolved base station (eNB or e-NodeB,evolutional Node B) in the LTE, which is not limited in the presentinvention; however, for the convenience of description, the eNode B istaken as an example for illustration in the following embodiments.

According to an existing LTE technology, one cell of a base stationcorresponds to one carrier. According to the embodiments of the presentinvention, carrier aggregation means that a carrier corresponding to acell of another base station is added for a UE accessing a base stationas a component carrier for the carrier aggregation. According to theembodiments of the present invention, when the carrier aggregation ismentioned, adding a cell of another base station for the UE and/oradding a data radio bearer (DRB, Data Radio Bearer) of another basestation for the UE may be involved.

It should be noted that, according to the embodiments of the presentinvention, cell aggregation between base stations may be classified intocell aggregation between macro base stations and cell aggregationbetween a macro base station and a micro base station (for example, aPico base station), a home base station (HeNB), or other types of basestations in a heterogeneous network (Heterogeneous network). In theembodiments of the present invention, the cell aggregation between macrobase stations is taken as an example for illustration.

According to the embodiments of the present invention, the concept of aprimary base station is introduced, that is, in a solution of carrieraggregation between base stations, there is a primary base station, andother serving base stations of the UE are used as secondary basestations. The UE accesses through a primary cell (PCell) of a primarybase station, and the primary base station decides whether to add a cell(that is, a secondary cell, SCell) of a secondary base station for theUE and control whether to set up a bearer on the secondary base station.For example, the primary base station may be a base station where the UEinitiates initial access, and the change of the primary base station inthe subsequent process requires an explicit instruction of a basestation.

FIG. 1 is a schematic flowchart of a method for implementing carrieraggregation according to an embodiment of the present invention. Themethod in FIG. 1 is performed by a base station (for example, a primarybase station for the carrier aggregation).

110: A primary base station determines to add a cell for a userequipment UE.

For example, the UE sets up an initial RRC (Radio Resource Control,radio resource control) connection in a cell of the primary basestation, that is, the primary base station is a control base station ofthe UE. The primary base station determines, according to a presetpolicy (for example, according to a measurement report reported by theUE and a trigger condition), whether to add a cell of a secondary basestation for the UE.

For example, after receiving an evolved radio access bearer (E-RAB,evolved Radio Access Bearer) setup request message from an MME (MobilityManagement entity, mobility management entity), the primary base stationmay determine, according to the preset policy, whether to add the cellof the secondary base station for the UE; however, the embodiment of thepresent invention is not limited thereto, for example, after receivingthe measurement report from the UE, the primary base station may alsodetermine, according to the preset policy, whether to add the cell ofthe secondary base station for the UE.

120: The primary base station sends a first message to the UE, where thefirst message is used to instruct the UE to add the cell, the firstmessage includes configuration information of the cell and an identifieror index of a base station to which the cell belongs, and the basestation to which the cell belongs is a secondary base station.

For example, the first message may be called an RRC connectionreconfiguration message. The foregoing configuration information of thecell of the secondary base station is used for the UE to configure thecell of the secondary base station, that is, add the cell of thesecondary base station. The identifier or index of the base station maybe included in a fixed location or preset cell of the RRC connectionreconfiguration message, and used to indicate that the base station towhich the cell belongs is a secondary base station, so that when the UEneeds to transmit data through the secondary base station, the UE mayselect, according to correspondence between the identifier or index ofthe secondary base station in the RRC connection reconfiguration messageand the cell of the secondary base station, to send the data through thecell of the secondary base station. The identifier of the base stationmay be a unique identifier, which is allocated by a network, of the basestation in the network, and the index of the base station may be anumber, which is allocated by the primary base station, of a servingbase station of the UE, so that the UE can distinguish between differentbase stations. In comparison with using the identifier of the basestation to distinguish between different base stations, using a shortindex to distinguish between different base stations can reduce asignaling overhead.

For example, the first message may have a message structure similar tothat of a regular RRC connection reconfiguration message, and thedifference lies in that the first message according to the embodiment ofthe present invention is further used to indicate a base station whichthe cell to be added belongs to. However, the embodiment of the presentinvention is not limited thereto, the foregoing first message may alsobe a new message specially used in the embodiment of the presentinvention. The foregoing cell may refer to at least one cell of thesecondary base station.

In the embodiment of the present invention, under the control of theprimary base station of the UE, the cell of the secondary base stationcan be added for the UE to implement carrier aggregation, so as tofurther increase the user throughput of the UE.

According to another embodiment of the present invention, the method inFIG. 1 further includes: before sending the first message to the UE,sending, by the primary base station, a second message to the secondarybase station for requesting the secondary base station to add the cellfor the UE, where the second message includes an identifier of the cell;and receiving, by the primary base station, a third message from thesecondary base station for responding to the second message, where thethird message includes configuration information of the cell.

For example, the second message may be called a secondary cell additionrequest (Scell Addition Request) message, and called a cell additionrequest message for short, or may be called an initial context setuprequest message. The third message may be called a secondary celladdition request response (Scell Addition Request ACK) message, andcalled a cell addition response message for short. For example, afterdetermining to add a cell (or a carrier) of another base station for theUE, the primary base station sends a cell addition request message tothe secondary base station through an X2/S1 interface, to request thesecondary base station to add the cell of the secondary base station forthe UE. The identifier of the cell of the secondary base station is usedto indicate which cell of the secondary base station is added by thesecondary base station for the UE. The identifier of the cell of thesecondary base station may be information used to distinguish betweendifferent cells, such as a physical cell identifier (PCI, Physical CellID) of the cell. The cell addition response message is used to instructwhether the secondary base station allows adding the cell for the UE. Ifthe secondary base station allows adding the cell for the UE, the celladdition response message may further include configuration informationof the cell of the secondary base station, where the cell of thesecondary base station is added for the UE.

For example, the foregoing RRC connection reconfiguration message may beincluded by the secondary base station in the foregoing cell additionrequest message, or may be generated by the primary base stationaccording to the foregoing cell addition response message. For example,the primary base station generates an RRC connection reconfigurationmessage, and includes the configuration information of the cell to beadded and an identifier or index of a base station to which the cell tobe added belongs in the RRC connection reconfiguration message.

According to another embodiment of the present invention, in the methodin FIG. 1, the second message is further used to request the secondarybase station to add a data radio bearer DRB for the UE, and the secondmessage further includes an identifier of the DRB and configurationinformation of an evolved radio access bearer E-RAB corresponding to theDRB.

For example, the cell addition request message further includes a DRB IDand a corresponding bearer parameter, so that the cell and the bearercan be added at the same time, so as to reduce the signaling overhead.However, the embodiment of the present invention is not limited thereto,the cell may be first added, and when a new service arrives, the DRB IDand the corresponding bearer parameter are carried by using a separatemessage.

According to the embodiment of the present invention, in step 120, thefirst message is further used to instruct the UE to add the DRB andassociate the DRB to the secondary base station, and the first messagefurther includes configuration information of the DRB, an identifier ofthe DRB, and an identifier or index of a base station to which the DRBis associated.

For example, the primary base station may instruct, through the RRCconnection reconfiguration message, the UE to perform configurationaccording to the configuration information of the DRB and the identifieror index of the base station, so as to add the DRB on the secondary basestation for the UE or add an DRB on another serving base station for theUE, and associate the DRB added for the UE to the secondary base stationor set up the DRB between the UE and the secondary base station. Inother words, associating the DRB to a base station refers totransferring related data of the DRB on the base station. The identifieror index of the base station may also be located at a fixed location orpreset cell of the RRC connection reconfiguration message and used toindicate which base station (for example, the secondary base station)sets up the DRB with the UE, so that when the UE needs to transmit dataof the foregoing DRB, the UE may select, according to correspondencebetween the identifier or index of the base station and the identifierof the DRB in the RRC connection reconfiguration message andcorrespondence between the identifier or index of the base station andthe added cell, a cell of the base station to send the data.

Optionally, in another embodiment, the method in FIG. 1 furtherincludes: sending, by the primary base station, a fifth message to theUE for instructing the UE to add the DRB and associate the DRB to thesecondary base station, where the fifth message includes theconfiguration information of the DRB, the identifier of the DRB, and theidentifier or index of the base station to which the DRB is associated.

For example, the fifth message may be called an RRC connectionreconfiguration message. For specific description, reference may be madeto the description of the first message, so the details are notdescribed herein again.

According to another embodiment of the present invention, the method inFIG. 1 further includes: before sending the fifth message to the UE,sending, by the primary base station, a sixth message to the secondarybase station for requesting the secondary base station to add the DRBfor the UE, where the sixth message includes the identifier of the DRBand the configuration information of the E-RAB corresponding to the DRB;and receiving, by the primary base station, a seventh message from thesecondary base station for responding to the sixth message, where theseventh message includes the configuration information of the DRB.

For example, the sixth message may be called a data radio beareraddition request message (DRB Addition Request), and called a beareraddition request message for short. The seventh message may be called abearer addition response message. After determining that the DRB on thesecondary base station needs to be added for the UE, the primary basestation sends an independent bearer addition request message to thesecondary base station through an X2/S1 interface. The bearer additionrequest message includes the identifier of the DRB that is allocated bythe primary base station and a bearer parameter (for example, theconfiguration information of the E-RAB) corresponding to the identifierof the DRB. According to the embodiment of the present invention, thecell of the secondary base station may be first added, and when a newservice arrives, the DRB is added and is associated to the secondarybase station, so as to reduce a service delay.

According to another embodiment of the present invention, in step 120,the first message is further used to instruct the UE to change the DRBfrom being associated to one base station to being associated to anotherbase station, and the first message includes the identifier of the DRBand an identifier or index of the another base station to which the DRBis associated.

For example, in a situation where the UE has set up a DRB on the primarybase station or secondary base station, if the DRB needs to be set up onanother base station according to a preset policy, the RRC connectionreconfiguration message may include an ID of the DRB that has been setup and an identifier or index of a new base station, so that the UE canmodify the configuration of the DRB and set up the DRB on the new basestation. For example, when a new service arrives, a DRB corresponding tothe new service may be immediately added and associated to the primarybase station, so as to transmit data of the new service on the primarybase station, which leads to a fast service connection and a low delay.Then, when learning, according to a measurement report reported by theUE, that the signal quality of the cell of the secondary base station isgood, the primary base station adds the cell of the secondary basestation and changes the DRB from being associated to the primary basestation to being associated to the secondary base station. Optionally,the DRB may be further changed from being associated to a secondary basestation to being associated to another secondary base station.

According to another embodiment of the present invention, in step 120,the first message is further used to instruct the UE and the secondarybase station to set up a signaling radio bearer (SRB, Signaling RadioBearer), and the third message and the first message both furtherinclude configuration information of the SRB.

For example, after it is determined that the cell of the secondary basestation is to be added for the UE, an SRB on the cell may be set up, sothat the secondary base station can directly perform signalinginteraction with the UE, so as to reduce transferring of signaling. Inaddition, in this case, when the cell and/or the DRB of the secondarybase station is added for the UE, the base station to which the addedcell belongs or the index of the base station may be indicated and/or anidentifier and/or index of a base station where the added DRB is locatedmay be indicated (that is, the base station to which the DRB isassociated is indicated). Optionally, the base station to which the DRBis associated may be not indicated, but by default, the base station towhich the DRB is associated is a base station to which a cell deliveringthe RRC connection reconfiguration message belongs.

According to another embodiment of the present invention, the method inFIG. 1 further includes: receiving, by the primary base station, afourth message from the secondary base station for learning that thecell is added successfully, where the fourth message includes an indexof the cell of the secondary base station, and the index of the cell ofthe secondary base station is allocated by the primary base station andis included in the second message.

For example, the fourth message may be called a cell addition successmessage, or may be called a secondary cell addition notification (SCellAddition Notify) message for short. After RRC connection reconfigurationis completed, the UE may initiate a random access process on the cell ofthe secondary base station, so as to perform synchronization with thecell of the secondary base station. After the random access of the UE iscompleted, the secondary base station may send a cell addition successmessage to the primary base station through the X2/S1 interface, so asto notify that the cell is added successfully. In addition, the index ofthe cell of the secondary base station may be allocated by the primarybase station, and which cell is added successfully is determined througha short cell index, so as to reduce the signaling overhead. The index ofthe cell of the secondary base station may be allocated by the primarybase station, for example, the cell of the secondary base station may benumbered by the primary base station.

Optionally, in another embodiment, the method in FIG. 1 furtherincludes: sending, by the primary base station, an identifier of theE-RAB and path information of the secondary base station to a mobilitymanagement entity, to request the mobility management entity to instructa serving gateway to send data of the E-RAB to the secondary basestation; or, forwarding, by the primary base station, the data, receivedfrom the serving gateway, of the E-RAB to the secondary base station.

For example, there may be two transmission solutions for sending servicedata to the UE through the secondary base station. The first one isthat, the serving gateway first sends the service data to the primarybase station, then, the primary base station forwards the service datato the secondary base station, and finally, the secondary base stationsends the service data to the UE. The other one is that, the identifierof the E-RAB and a path of the secondary base station are carriedthrough an independent path switch request (PATH SWITCH REQUEST)message, for indicating that service data of the E-RAB is switched to aneNB2, and then, the serving gateway directly sends the service data tothe secondary base station, so as to reduce transferring of the servicedata. Optionally, the foregoing identifier of the E-RAB and the path ofthe secondary base station may be carried in an E-RAB setup response(E-RAB SETUP RESPONSE) message.

Optionally, in another embodiment, after the RRC connectionreconfiguration is completed, the primary base station may receive anRRC connection reconfiguration completion message from the UE.

According to the embodiment of the present invention, cell aggregationbetween macro base stations can increase the data throughput of a userequipment at an edge of a base station and improve the user experience.In addition, when the embodiment of the present invention is applied ina heterogeneous network, cell aggregation between a macro base stationand a micro base station or an HeNB not only can increase the datathroughput of a user equipment but also can distribute the system loadof a macro network, and can reduce the occurrence of switchover incomparison with a pure HeNB network.

FIG. 2 is a schematic flowchart of a method for implementing carrieraggregation according to another embodiment of the present invention.The method in FIG. 2 is performed by a base station (for example, aprimary base station for the carrier aggregation).

210: The primary base station determines to add a DRB for a UE.

For example, the UE sets up an initial RRC connection in a cell of theprimary base station, that is, the primary base station is used as acontrol base station of the UE. The primary base station determines,according to a preset policy (for example, according to a measurementreport reported by the UE and a trigger condition), whether to add a DRBon a secondary base station for the UE. After receiving an E-RAB setuprequest from an MME, the primary base station determines, according tothe preset policy, whether to add the DRB on the secondary base stationfor the UE; however, the embodiment of the present invention is notlimited thereto, for example, the primary base station may alsodetermine, according to the preset policy, whether to add the DRB on thesecondary base station for the UE after the cell is added or after themeasurement report is received from the UE.

220: The primary base station sends a fifth message to the UE forinstructing the UE to add the DRB and associate the DRB to the secondarybase station, where the fifth message includes configuration informationof the DRB, an identifier of the DRB, and an identifier or index of thebase station to which the DRB is associated, and the base station towhich the DRB is associated is the secondary base station.

For example, the fifth message may be called an RRC connectionreconfiguration message. The foregoing configuration information of theDRB is used by the UE to configure the foregoing DRB, so as to add theforegoing DRB. The identifier or index of the base station may belocated at a fixed location or preset cell of the RRC connectionreconfiguration message and used to indicate which base station (forexample, the secondary base station) sets up the DRB with the UE, sothat when the UE needs to transmit data of the foregoing DRB, the UE mayselect, according to correspondence between the identifier of the DRBand the foregoing identifier or index of the base station in the RRCconnection reconfiguration message and correspondence between theidentifier or index of the base station and the added cell, to send thedata through a cell of the base station (for example, an added cell ofthe secondary base station). For example, the fifth message may have amessage structure similar to that of a regular RRC connectionreconfiguration message, and the difference lies in that the fifthmessage according to the embodiment of the present invention is furtherused to indicate which base station the cell to be added belongs to.However, the embodiment of the present invention is not limited thereto,the foregoing RRC connection reconfiguration message may also be a newmessage specially used in the embodiment of the present invention. Theforegoing DRB may refer to at least one DRB.

In the embodiment of the present invention, under the control of theprimary base station of the UE, a DRB on another base station can beadded for the UE, so as to implement the carrier aggregation, therebyfurther increasing the user throughput of the UE. In addition, accordingto the embodiment of the present invention, the process of adding theDRB may be independent from the process of adding the cell, so that thecell may be first added, and the DRB is added after a new servicearrives, so as to reduce a service delay.

In step 220, before sending the fifth message to the UE, the primarybase station sends a sixth message to the secondary base station forrequesting the secondary base station to add the DRB for the UE, wherethe sixth message includes the identifier of the DRB and configurationinformation of an E-RAB corresponding to the DRB; and the primary basestation receives a seventh message from the secondary base station forresponding to the sixth message, where the seventh message includes theconfiguration information of the DRB.

For example, the sixth message may be called a bearer addition requestmessage. The seventh message may be called a bearer addition responsemessage. For example, after determining that the DRB on the secondarybase station needs to be added for the UE, the primary base station maysend a bearer addition request message to the secondary base stationthrough an X2/S1 interface. The bearer addition request message includesa DRB ID allocated by the primary base station and a bearer parameter(for example, the configuration information of the E-RAB) correspondingto the DRB ID.

Optionally, in another embodiment, the method in FIG. 2 furtherincludes: sending, by the primary base station, an identifier of theE-RAB and path information of the secondary base station, to an MME, soas to request the MME to instruct a serving gateway to send data of theE-RAB to the secondary base station; or, forwarding, by the primary basestation, the data, received from the serving gateway, of the E-RAB tothe secondary base station.

For example, there may be two transmission solutions for sending servicedata to the UE through the secondary base station. The first one isthat, the serving gateway first sends the service data to the primarybase station, then, the primary base station forwards the service datato the secondary base station, and finally, the secondary base stationsends the service data to the UE. The other one is that, the identifierof the E-RAB and a path of the secondary base station are carriedthrough an independent path switch request message, for indicating thata service data stream of the E-RAB is switched to an eNB2, and then, theserving gateway directly sends the service data to the secondary basestation, so as to reduce transferring of the service data. Optionally,the identifier of the E-RAB and the path of the secondary base stationmay be carried in an E-RAB setup response message.

FIG. 3 is a schematic flowchart of a method for implementing carrieraggregation according to another embodiment of the present invention.The method in FIG. 3 is performed by a base station (for example, asecondary base station for the carrier aggregation). The method in FIG.3 corresponds to the method in FIG. 1, so the details are not describedherein again.

310: A secondary base station receives a second message from a primarybase station, where the second message is used to request the secondarybase station to add a cell of the secondary base station for a userequipment UE, and the second message includes an identifier of the cellof the secondary base station.

320: The secondary base station adds the cell of the secondary basestation for the UE according to the second message.

For example, the second message may be called a cell addition requestmessage. For example, the secondary base station performs admissioncontrol according to the identifier of the cell of the secondary basestation that is included in the cell addition request message, so as todetermine whether to add the cell of the secondary base station for theUE.

In the embodiment of the present invention, under the control of theprimary base station of the UE, a cell of another base station can beadded for the UE, so as to implement the carrier aggregation, therebyfurther increasing the user throughput of the UE.

Optionally, in another embodiment, the method in FIG. 3 furtherincludes: sending, by the secondary base station, a third message to theprimary base station for responding to the second message, where thethird message includes configuration information of the cell of thesecondary base station. For example, the third message may be called acell addition response message.

Optionally, in another embodiment, in step 320, the second message isfurther used to request the secondary base station to add a data radiobearer DRB for the UE, and the second message further includes anidentifier of the DRB and configuration information of an evolved radioaccess bearer E-RAB corresponding to the DRB. The method in FIG. 3further includes: adding, by the secondary base station, the DRB for theUE according to the second message.

For example, the secondary base station performs configuration accordingto the identifier of the DRB and the configuration information of theE-RAB that are included in the cell addition request message, so as toadd the DRB for the UE.

Optionally, in another embodiment, in step 320, the third messagefurther includes configuration information of a signaling radio bearerSRB.

Optionally, in another embodiment, the method in FIG. 3 furtherincludes: sending, by the secondary base station, a fourth message tothe primary base station for notifying the primary base station that thecell is added successfully, where the fourth message includes an indexof the cell of the secondary base station, and the index of the cell ofthe secondary base station is allocated by the primary base station andincluded in the fourth message, for example, the fourth message may becalled a cell addition success message.

FIG. 4 is a schematic flowchart of a method for implementing carrieraggregation according to another embodiment of the present invention.The method in FIG. 4 is performed by a base station (for example, asecondary base station for the carrier aggregation). The method in FIG.4 corresponds to the method in FIG. 2, so the details are not describedherein again.

410: A secondary base station receives a sixth message from a primarybase station, where the sixth message is used to request the secondarybase station to add a DRB for a UE and includes an identifier of the DRBand configuration information of an E-RAB corresponding to the DRB.

420: The secondary base station sends a seventh message to the primarybase station for responding to a bearer addition request message, wherethe bearer addition response message includes configuration informationof the DRB. For example, the sixth message may be called a beareraddition request message, and the seventh message may be called a beareraddition response message.

In the embodiment of the present invention, under the control of theprimary base station of the UE, a cell of another base station can beadded for the UE, so as to implement the carrier aggregation, therebyfurther increasing the user throughput of the UE.

FIG. 5 is a schematic flowchart of a method for implementing carrieraggregation according to another embodiment of the present invention.The method in FIG. 5 is performed by a UE. The method in FIG. 5corresponds to the method in FIG. 1, so the details are not describedherein again.

510: A user equipment UE receives a first message from a primary basestation, where the first message is used to instruct the UE to add acell, the first message includes configuration information of the celland an identifier or index of a base station to which the cell belongs,and the base station to which the cell belongs is a secondary basestation.

520: The UE adds the cell according to the first message.

For example, the first message may be called an RRC connectionreconfiguration message. The UE performs configuration according toconfiguration information of a cell of the secondary base station and anidentifier or index of a base station to which the cell to be addedbelongs that are included in the RRC connection reconfiguration message,so as to add the cell of the secondary base station. When the UE needsto send data through the secondary base station, the UE may send thedata through the cell of the secondary base station according tocorrespondence between the identifier or index of the base station towhich the cell to be added belongs in the RRC connection reconfigurationmessage and the cell of the secondary base station.

Optionally, in another embodiment, in step 510, the first message isfurther used to instruct the UE to add a data radio bearer DRB andassociate the DRB to the secondary base station, and the first messagefurther includes an identifier of the DRB, configuration information ofthe DRB, and the identifier or index of the base station to which theDRB is associated. The method in FIG. 5 further includes: adding, by theUE according to the first message, the DRB and associating the DRB tothe secondary base station.

For example, when the UE needs to send data of the DRB, the UE maydetermine, according to correspondence between the identifier or indexof the secondary base station in the RRC connection reconfigurationmessage and the cell of the secondary base station and correspondencebetween the identifier or index of the secondary base station and theidentifier of the DRB, to send the data through the cell of thesecondary base station. The identifier or index of the secondary basestation and an identifier or index of a base station to which the cellto be added belongs may be located in the same location or cell of theRRC connection reconfiguration message, or may be located in differentlocations or cells of the RRC connection reconfiguration message.

Optionally, in another embodiment, the method in FIG. 5 furtherincludes: receiving, by the UE, a fifth message from the primary basestation, where the fifth message is used to instruct the UE to add theDRB and associate the DRB to the secondary base station, and the fifthmessage includes the configuration information of the DRB, theidentifier of the DRB, and an identifier or index of a secondary basestation setting up the DRB with the UE. The UE adds the DRB andassociates the DRB to the secondary base station according to the fifthmessage. For example, the fifth message may be called an RRC connectionreconfiguration message.

Optionally, in another embodiment, in step 510, the first message isfurther used to instruct the UE to change the DRB from being associatedto one base station to being associated to another base station, and thefirst message includes the identifier of the DRB and an identifier orindex of the another base station to which the DRB is associated. Themethod in FIG. 5 further includes: changing the DRB from beingassociated to one base station to being associated to another basestation.

Optionally, in another embodiment, in step 510, the first message isfurther used to instruct the UE to set up a signaling radio bearer SRBwith the secondary base station, and the first message further includesconfiguration information of the SRB. The method in FIG. 5 furtherincludes: setting up, by the UE, the SRB with the secondary base stationaccording to the first message.

In the embodiment of the present invention, under the control of theprimary base station of the UE, a cell of another base station can beadded for the UE, so as to implement the carrier aggregation, therebyfurther increasing the user throughput of the UE.

FIG. 6 is a schematic flowchart of a method for implementing carrieraggregation according to another embodiment of the present invention.The method in FIG. 6 is performed by a UE. The method in FIG. 6corresponds to the method in FIG. 2, so the details are not describedherein again.

610: A UE receives a fifth message from a primary base station, wherethe fifth message is used to instruct the UE to add a DRB and associatethe DRB to a secondary base station, and the fifth message includesconfiguration information of the DRB, an identifier of the DRB, anidentifier or index of a secondary base station setting up the DRB withthe UE.

620: The UE adds the DRB and associates the DRB to the secondary basestation according to the fifth message. For example, the fifth messagemay be called an RRC connection reconfiguration message.

In the embodiment of the present invention, under the control of theprimary base station of the UE, a cell of another base station can beadded for the UE, so as to implement the carrier aggregation, therebyfurther increasing the user throughput of the UE.

Optionally, in another embodiment, the method in FIG. 6 furtherincludes: receiving, by the UE, data of the DRB from the secondary basestation; or sending, by the UE, data of the DRB to the secondary basestation.

The embodiment of the present invention is described in detail in thefollowing with reference to specific examples. It should be noted that,in the following embodiment of the present invention, cell aggregationbetween macro base stations is taken as an example for illustration, forexample, a primary base station (for example, an eNB1) of a UE is aprimary base station for carrier aggregation between base stations,another serving base station (for example, an eNB2) of the UE is asecondary base station. However, the embodiment of the present inventionis not limited thereto, for example, the primary base station for thecarrier aggregation may be a macro base station, and the secondary basestation may be a micro base station (for example, a Pico base station)or a home base station (HeNB). The present invention is not limited tospecific standards represented by the foregoing terms but may besimilarly applied in a base station of another form.

FIG. 7 is a schematic flowchart of a process of implementing carrieraggregation according to an embodiment of the present invention.

705: A UE sets up an initial RRC connection with a cell 1 (Cell1) of aneNB1.

710: The UE performs measurement according to a measurement controlmessage delivered by the eNB1, so as to obtain a measurement result suchas signal quality information of a neighboring cell (for example, aneNB2) of the eNB1 and report it to the eNB1.

715: When a new service arrives, an MME sends an S1 message, that is, anE-RAB setup request (E-RAB SETUP REQUEST) to the eNB1 through an S1interface for requesting setting up a new E-RAB.

718: After receiving the E-RAB setup request, the eNB1 determines,according to a preset policy, that a cell 2 (Cell2) of the eNB2 needs tobe added for the UE and a bearer (DRB) corresponding to the E-RAB needsto be set up on the eNB2. Optionally, the eNB1 may allocate a cell index(cell index) of the Cell2 and an identifier (DRB ID) of the DRBcorresponding to the E-RAB. The DRB ID or the cell index is uniformlyallocated by the eNB1, thereby avoiding that the DRB ID or the cellindex incurs a collision at the UE side. For example, if each of theeNB1 and eNB2 allocates a DRB ID when setting up a corresponding DRB,the same DRB ID may be allocated to different DRBs, resulting in thattwo DRBs having the same ID exist at a UE side. The foregoing presetpolicy may be that the signal quality of a neighboring cell meets apreset threshold and/or a cell of a primary base station fails to meetthe data throughput requirement of the UE. For example, the eNB1 maylearn, through the measurement result reported by the UE, whether thesignal quality of the Cell2 of the eNB2 meets the preset threshold.

720: The eNB1 sends a cell addition request (Scell Addition Request)message to the eNB2. The cell addition request message may be called aninitial context setup request message and is similar to an initialcontext setup request message sent between a mobility management entityand an eNB. The cell addition request message may carry a cell index ofthe Cell2 and corresponding cell information (including a frequency anda PCI of a cell), for adding the cell. The cell addition request messagemay further carry the DRB ID and a corresponding E-RAB related parameter(mainly including a QoS (Quality of Service) parameter such as apriority and a guaranteed rate), for adding a DRB.

725: After receiving the cell addition request message, the eNB2 mayperform admission control according to the foregoing information carriedin the cell addition request message, so as to determine whether to adda cell of the eNB2 for the UE; then, the eNB2 may send a cell additionresponse (Scell Addition Request ACK) message to the eNB1. The celladdition response message includes configuration information related tocell addition, for example, configuration information such as afrequency band and a PCI of the Cell2, antenna information of the Cell2,and a physical channel, and further includes configuration informationrelated to DRB addition, for example, PDCP (packet data convergenceprotocol, Packet Data Convergence Protocol) configuration information,RLC (Radio Link Control, radio link control) configuration information,and logical channel configuration information of the DRB. Optionally,the cell addition response message may include an RRC connectionreconfiguration (RRC Connection Reconfiguration) message, where the RRCconnection reconfiguration message includes the configurationinformation related to cell addition, and indicates a base station towhich an added cell belongs, for example, an identifier or index of thebase station to which the added cell belongs is included in a fixedlocation or preset cell of the RRC connection reconfiguration message.The RRC connection reconfiguration message further includes theconfiguration information related to DRB addition and indicates a basestation (eNB2) associated to the DRB, that is, a base station setting upthe DRB with the UE, for example, an identifier or index of the basestation setting up the DRB with the UE is included in a fixed locationor preset cell of the RRC connection reconfiguration message.Optionally, when the base station setting up the DRB with the UE and thebase station to which the added cell belongs are the same, theidentifier or index of the base station setting up the DRB with the UEand the identifier or index of the base station to which the added cellbelongs may be located in the same location or cell in the RRCconnection reconfiguration message.

730: After receiving the cell addition response message from the eNB2,the eNB1 generates an RRC connection reconfiguration message, and sendsit to the UE. The RRC connection reconfiguration message includes theconfiguration information related to cell addition, and indicates a basestation to which the added cell belongs; and includes the configurationinformation related to DRB addition, and indicates a base station (eNB2)associated to the DRB. Optionally, in a situation where the celladdition response message includes the RRC connection reconfigurationmessage, the RRC connection reconfiguration message included in the celladdition response message may be directly sent to the UE.

735: After receiving the RRC connection reconfiguration message, the UEperforms configuration according to the related configurationinformation included in the RRC connection reconfiguration message, soas to add the cell of the eNB2 and associate the DRB to the eNB2, thatis, set up the DRB with the eNB2; then, the UE sends an RRC connectionreconfiguration completion (RRC Connection Reconfiguration Complete)message to the eNB1.

740: The UE initiates a random access process on the new cell Cell2, soas to perform synchronization with the Cell2. Optionally, the sequenceof steps 735 and 740 may be reversed.

760: After the random access of the UE succeeds, the eNB2 sends a celladdition success (SCELL ADDITION NOTIFY) message to the eNB1 fornotifying the eNB1 that the cell is added successfully. Optionally, thecell addition success message may carry the index of the Cell2 forindicating that the Cell2 of the eNB2 is added successfully.

770: After receiving the cell addition success message, the eNB1 sendsan E-RAB setup response (E-RAB SETUP RESPONSE) message to the MME, so asto notify the MME that an E-RAB is set up successfully.

Optionally, the E-RAB setup response message may carry an identifier ofthe E-RAB and a path of the eNB2, for example, a transport layer addressand GTP (General Packet Radio Service Tunnel Protocol, general packetradio service tunnel protocol)-TEID (Tunnel Endpoint ID, tunnel endpointidentifier), for indicating that service data of the E-RAB is switchedto the eNB2, that is, requesting the MME to instruct a serving gateway(serving-Gateway) (not shown) to send a data stream of the E-RAB to theeNB2. In this case, after step 770, steps 785 and 790 are performed.

Optionally, if the identifier of the E-RAB and the path of the eNB2 arecarried through an independent message, steps 775 to 790 may beperformed after step 770.

775: The eNB1 sends an independent path switch request (PATH SWITCHREQUEST) message to the MME, for indicating that the service data of theE-RAB is switched to the eNB2, where the message may carry theidentifier of the E-RAB and the path of the eNB2.

780: The eNB2 sends a path switch request response (ACK,Acknowledgement) message to the eNB1 for responding to the path switchrequest.

785: After receiving a request for switching the service data of theE-RAB to the eNB2, the serving gateway directly sends the data to theeNB2.

790: The eNB2 forwards, to the UE, new service data received from theserving gateway.

Optionally, for the service data that needs to be sent to the UE by theeNB2, the service data may also be first sent by the serving gateway tothe eNB1 and then forwarded by the eNB1 to the eNB2.

In the embodiment in FIG. 7, when a new service arrives, a primary basestation of the UE determines to add a cell of a secondary base stationfor the UE, and at the same time, adds a DRB corresponding to the newservice, and allocates the DRB to the secondary base station, so as toreduce signaling interaction, thereby reducing a signaling overhead.

FIG. 8 is a schematic flowchart of a process of implementing carrieraggregation according to another embodiment of the present invention.

805: A UE sets up an initial RRC connection with a Cell1 of an eNB1.

810: The UE performs measurement according to a measurement controlmessage delivered by the eNB1, so as to obtain a measurement result suchas signal quality information of a neighboring cell (for example, aneNB2) of the eNB1.

818: The eNB1 decides to add a Cell2 of the eNB2 for the UE according toa preset policy. Optionally, the eNB1 may allocate a cell index to theCell2. The preset policy in step 818 is similar to the preset policy instep 718 in FIG. 7, so the details are not described herein again.

820: The eNB1 sends a cell addition request message to the eNB2. Thecell addition request message may be called an initial context setuprequest message and is similar to an initial context setup requestmessage sent between a mobility management entity and an eNB. The celladdition request message may carry cell information (including afrequency band and a PCI of a cell) for adding the cell. Optionally, thecell addition request message may further carry the cell index of theCell2.

825: After receiving the cell addition request message, the eNB2 mayperform admission control according to the foregoing information carriedin the cell addition request message, so as to determine whether to adda cell of the eNB2 for the UE; then, the eNB2 may send a cell additionresponse message to the eNB1. The cell addition response messageincludes configuration information related to cell addition, forexample, configuration information such as a frequency band and a PCI ofthe Cell2, antenna information of the Cell2, and a physical channel.Optionally, the cell addition response message may include an RRCconnection reconfiguration message, where the RRC connectionreconfiguration message includes the configuration information relatedto cell addition, and indicates a base station to which an added cellbelongs, for example, an ID or index of the base station to which theadded cell belongs may be included in a fixed location or preset cell ofthe RRC connection reconfiguration message.

830: After receiving the cell addition response message from the eNB2,the eNB1 generates an RRC connection reconfiguration message, and sendsit to the UE. The RRC connection reconfiguration message includes theconfiguration information related to cell addition, and indicates thebase station to which the added cell belongs. Optionally, in a situationwhere the cell addition response message includes the RRC connectionreconfiguration message, the RRC connection reconfiguration messageincluded in the cell addition response message may be directly sent tothe UE.

835: After receiving the RRC connection reconfiguration message, the UEperforms configuration according to the related configurationinformation included in the RRC connection reconfiguration message, soas to add the cell of the eNB2; then, the UE may send an RRC connectionreconfiguration completion message to the eNB1.

840: The UE initiates a random access process on the new cell Cell2, soas to perform synchronization with the Cell2. Optionally, the sequenceof steps 835 and 840 may be reversed.

845: After the random access of the UE succeeds, the eNB2 sends a celladdition success message to the eNB1 for notifying the eNB1 that theCell2 is added successfully. Optionally, the cell addition successmessage may carry the index of the Cell2, for indicating that the Cell2of the eNB2 is added successfully.

848: When a new service arrives, an MME sends an S1 message, that is, anE-RAB setup request, to the eNB1 through an S1 interface, for requestingsetting up a new E-RAB.

850: After receiving the E-RAB setup request, the eNB1 determines,according to a preset policy, that a bearer corresponding to the E-RABneeds to be set up on the eNB2. Optionally, the eNB1 may allocate a DRBID corresponding to the E-RAB. The foregoing preset policy may be thatthe signal quality of a neighboring cell meets a preset threshold and/orthe data throughput of the UE fails to meet a requirement.

855: The eNB1 sends a bearer addition request message (DRB ADDITIONRequest) to the eNB2, where the bearer addition request message maycarry the DRB ID and a corresponding E-RAB related parameter (mainlyincluding a QoS parameter such as a priority and a guaranteed rate), foradding a DRB.

858: After receiving the bearer addition request message, the eNB2 mayperform admission control according to the foregoing information carriedin the bearer addition request message, so as to determine whether toadd the DRB for the UE on the eNB2. The eNB2 may send a bearer additionresponse (DRB ADDITION Request ACK) message to the eNB1, so as to notifythe eNB1 that the bearer is added successfully, where the beareraddition response message includes configuration information related toDRB addition, for example, PDCP configuration information, RLCconfiguration information, and logical channel configuration informationof the DRB. Optionally, the bearer addition response message may includean RRC connection reconfiguration message, where the RRC connectionreconfiguration message includes the configuration information relatedto DRB addition, and indicates a base station (eNB2) associated to theDRB, for example, an identifier or index of the base station setting upthe DRB with the UE is included in a fixed location or preset cell ofthe RRC connection reconfiguration message.

860: After receiving the bearer addition response message from the eNB2,the eNB1 generates an RRC connection reconfiguration message, and sendsit to the UE. Step 860 is similar to step 730 in FIG. 7, so the detailsare not described herein again.

865: After receiving the RRC connection reconfiguration message, the UEperforms configuration according to the related configurationinformation included in the RRC connection reconfiguration message, soas to add the DRB and associate the DRB to the eNB2, that is, set up theDRB with the eNB2; then, the UE sends an RRC connection reconfigurationcompletion message to the eNB1.

868: The eNB1 sends a bearer addition success notification message tothe eNB2 for notifying that the DRB is added successfully.

Steps 870, 875, 880, 885, and 890 are similar to steps 770, 775, 780,785, and 790 in FIG. 7, so the details are not described herein again.

In the embodiment in FIG. 8, a cell of a secondary base station is firstadded, and when a new service arrives, the DRB is added and isassociated to the secondary base station, so as to reduce a servicedelay.

FIG. 9 is a schematic flowchart of a process of implementing carrieraggregation according to another embodiment of the present invention.

905: A UE sets up an initial RRC connection with a Cell1 of an eNB1.

910: When a new service arrives, an MME sends an S1 message, that is, anE-RAB setup request message to the eNB1 through an S1 interface, forrequesting setting up a new E-RAB.

915: The eNB1 generates an RRC connection reconfiguration message, wherethe RRC connection reconfiguration message includes configurationinformation related to DRB addition and indicates a base station (eNB1)associated to a DRB, for example, an identifier or index of a basestation setting up the DRB with the UE is included in a fixed locationor preset cell of the RRC connection reconfiguration message; then, theeNB1 sends the RRC connection reconfiguration message to the UE.

920: The UE performs configuration according to the relatedconfiguration information included in the RRC connection reconfigurationmessage, so as to add the DRB and set up the DRB with the eNB1; then,the UE may send an RRC connection reconfiguration completion message tothe eNB1.

925: The eNB1 sends an E-RAB setup response to the MME, so as to notifythe MME that an E-RAB is set up successfully.

930: The new service may be sent to the UE by the eNB1.

935: The UE performs measurement according to a measurement controlmessage delivered by the eNB1, so as to obtain a measurement result suchas signal quality information of a neighboring cell (for example, aneNB2) of the eNB1.

938: Determine, according to a preset policy, to add a Cell2 of the eNB2for the UE, and associate a DRB corresponding to the E-RAB to the eNB2.Optionally, the eNB1 may allocate a cell index to the Cell2. Step 938 issimilar to step 718 in FIG. 7, so the details are not described hereinagain.

940: The eNB1 sends a cell addition request message (or called aninitial context setup request message) to the eNB2 and carries a cellindex and corresponding cell information (including a frequency band anda PCI of a cell), for adding the cell, and carries an ID of the DRB thatis previously set up, for instructing the UE to associate the DRB to theeNB2, that is to say, change the DRB that is set up with the eNB1 tosetting up the DRB with the eNB2.

945: After receiving the cell addition request message, the eNB2 mayperform admission control according to the foregoing information carriedin the cell addition request message, so as to determine whether to adda cell of the eNB2 for the UE and whether to add the DRB for the UE onthe eNB2; then, the eNB2 may send a cell addition response message tothe eNB1, where the cell addition response message may includeconfiguration information related to cell addition. Optionally, the celladdition response message may include an RRC connection reconfigurationmessage, where the RRC connection reconfiguration message may includethe configuration information related to cell addition and indicate abase station to which an added cell belongs, and the RRC connectionreconfiguration message further includes the ID of the DRB that has beenset up and an identifier or index of a new base station setting up theDRB with the UE, for instructing the UE to associate the DRB to the newbase station.

950: After receiving the cell addition response message from the eNB2,the eNB1 generates an RRC connection reconfiguration message, and sendsit to the UE. The RRC connection reconfiguration message includes theconfiguration information related to cell addition, and indicates thebase station to which the added cell belongs, and the RRC connectionreconfiguration message further includes the ID of the DRB that has beenset up and the identifier or index of the new base station setting upthe DRB with the UE, for instructing to associate the DRB to the newbase station, that is to say, change the DRB from being associated toone base station to being associated to another base station.Optionally, in a situation where the cell addition response messageincludes the RRC connection reconfiguration message, the RRC connectionreconfiguration message included in the cell addition response messagemay be directly sent to the UE.

955: The UE sends an RRC connection reconfiguration completion messageto the eNB1.

960: The UE initiates a random access process on the new cell Cell2, soas to perform synchronization with the Cell2. The sequence of steps 955and 960 may be reversed.

965: After the random access of the UE succeeds, the eNB2 sends a celladdition success message to the eNB1 and carries an index of the Cell2,for notifying the eNB1 that the Cell2 is added successfully.

Steps 975, 980, 985, and 990 are similar to steps 775, 780, 785, and 790in FIG. 7 respectively, so the details are not described herein again.

In the embodiment in FIG. 9, when a new service arrives, a DRBcorresponding to the new service is immediately added and associated toa primary base station, so as to first transmit data of the service onthe primary base station, which leads to a fast service connection and alow delay, and then, it is obtained through measurement that the signalquality of a cell of a secondary base station is good, the cell of thesecondary base station is added and the DRB is changed from beingassociated to the primary base station to being associated to thesecondary base station.

FIG. 10 is a schematic flowchart of a process of implementing carrieraggregation according to another embodiment of the present invention.

1005: A UE sets up an initial RRC connection with a Cell1 of an eNB1.

1010: The UE performs measurement according to a measurement controlmessage delivered by the eNB1, so as to obtain a measurement result suchas signal quality information of a neighboring cell (for example, aneNB2) of the eNB1.

1015: When a new service arrives, an MME sends an S1 message, that is,an E-RAB setup request message, to the eNB1 through an S1 interface, forrequesting setting up a new E-RAB.

1018: After receiving the E-RAB setup request, the eNB1 determines,according to a preset policy, that a Cell2 of the eNB2 needs to be addedfor the UE and a bearer corresponding to an E-RAB needs to be set up onthe eNB2, which is similar to step 718 in FIG. 7, so the details are notdescribed herein again.

1020: The eNB1 sends a cell addition request message to the eNB2, whichis similar to step 820 in FIG. 8, so the details are not describedherein again.

1025: After receiving the cell addition request message, the eNB2 mayperform admission control according to the foregoing information carriedin the cell addition request message, so as to determine whether to adda cell of the eNB2 for the UE; then, the eNB2 may send a cell additionresponse message to the eNB1. The cell addition response messageincludes configuration information related to cell addition, forexample, configuration information such as a frequency band and a PCI ofthe Cell2, antenna information of the Cell2, and a physical channel, andrelated configuration information of a SRB, for example, RLCconfiguration information and logical channel configuration information.Optionally, the cell addition response message may include an RRCconnection reconfiguration message, where the RRC connectionreconfiguration message includes the configuration information relatedto cell addition, and indicates a base station to which an added cellbelongs and the related configuration information of the SRB. Forexample, an ID or index of a base station to which the added cellbelongs may be included in a fixed location or preset cell of the RRCconnection reconfiguration message, so as to indicate the base stationto which the added cell belongs.

1030: After receiving the cell addition response message from the eNB2,the eNB1 generates an RRC connection reconfiguration message, and sendsit to the UE. The RRC connection reconfiguration message includes theconfiguration information related to cell addition and the relatedconfiguration information of the SRB, and indicates the base station towhich the added cell belongs. Optionally, in a situation where the celladdition response message includes the RRC connection reconfigurationmessage, the RRC connection reconfiguration message included in the celladdition response message may be directly sent to the UE.

1035: The UE initiates a random access process on the new cell Cell2, soas to perform synchronization with the Cell2.

1040: The UE sends an RRC connection reconfiguration completion messageto the eNB2. Optionally, the sequence of steps 1035 and 1040 may bereversed.

1045: The eNB2 sends a cell addition success message to the eNB1, fornotifying the eNB1 that the cell Cell2 is added successfully. Step 1045is similar to step 845 in FIG. 8, so the details are not describedherein again.

1050: The eNB1 sends a bearer addition request message, where the beareraddition request message may carry a DRB ID and a corresponding E-RABrelated parameter (mainly including a QoS parameter such as a priorityand a guaranteed rate), for adding a DRB.

1055: After receiving the bearer addition request message, the eNB2 mayperform admission control according to the foregoing information carriedin the bearer addition request message, so as to determine whether toadd the DRB for the UE on the eNB2. The eNB2 may generate an RRCconnection reconfiguration message, and directly send the RRC connectionreconfiguration message to the UE, where the RRC connectionreconfiguration message includes configuration information related toDRB addition, and indicates a base station (for example, the eNB2)associated to the DRB. Optionally, by default, a base station receivingthe RRC connection reconfiguration message may be the base station to beassociated.

1060: The UE sends an RRC connection reconfiguration completion messageto the eNB2.

1065: The eNB2 sends a bearer addition response message, so as to notifythe eNB1 that the DRB is added successfully.

Steps 1070, 1075, 1080, 1085, and 1090 are similar to steps 770, 775,780, 785, and 790 in FIG. 7, so the details are not described hereinagain.

In the embodiment in FIG. 10, when a cell of a secondary base station isadded, an SRB on the cell is set up at the same time, so that a basestation where the cell is located is capable of directly performingsignaling interaction with the UE, so as to reduce transferring ofsignaling.

The method for implementing carrier aggregation according to theembodiments of the present invention is described above, and a basestation and a UE for implementing carrier aggregation according to theembodiments of the present invention are described in the following withreference to FIG. 11 to FIG. 16.

FIG. 11 is a schematic structural diagram of a base station 1100according to another embodiment of the present invention. The basestation 1100 may be used as a primary base station for carrieraggregation. The base station 1100 includes a determining module 1110and a sending module 1120.

The determining module 1110 determines to add a cell for a userequipment UE. The sending module 1120 sends a first message to the UE,where the first message is used to instruct the UE to add the cell, thefirst message includes configuration information of the cell and anidentifier or index of a base station to which the cell belongs, and thebase station to which the cell belongs is a secondary base station.

In the embodiment of the present invention, under the control of theprimary base station of the UE, a cell of another base station can beadded for the UE, so as to implement the carrier aggregation, therebyfurther increasing the user throughput of the UE.

Optionally, in another embodiment, before sending the first message tothe UE, the sending module 1120 further sends a second message to thesecondary base station, where the second message is used to request thesecondary base station to add the cell for the UE and includes anidentifier of the cell. The base station further includes a receivingmodule 1130. The receiving module 1130 receives a third message from thesecondary base station, where the third message is used to respond tothe second message and includes the configuration information of thecell.

Optionally, in another embodiment, the second message is further used torequest the secondary base station to add a DRB for the UE, and thesecond message further includes an identifier of the DRB andconfiguration information of an evolved radio access bearer E-RABcorresponding to the DRB.

Optionally, in another embodiment, the first message is further used toinstruct the UE to add the DRB and associate the DRB to the secondarybase station, and the first message further includes configurationinformation of the DRB, the identifier of the DRB, and the identifier orindex of the base station to which the DRB is associated. Optionally, inanother embodiment, the sending module 1120 further sends a fifthmessage to the UE, for instructing the UE to add the DRB and associatethe DRB to the secondary base station, where the fifth message includesthe configuration information of the DRB, the identifier of the DRB, andthe identifier or index of the base station to which the DRB isassociated.

Optionally, in another embodiment, before sending the fifth message tothe UE, the sending module 1120 sends a sixth message to the secondarybase station, for requesting the secondary base station to add the DRBfor the UE, where the sixth message includes the identifier of the DRBand the configuration information of the E-RAB corresponding to the DRB;and the sending module 1120 receives and bears a seventh message fromthe secondary base station, for responding to the sixth message, wherethe seventh message includes the configuration information of the DRB.

Optionally, in another embodiment, the first message is further used toinstruct the UE to set up a signaling radio bearer SRB with thesecondary base station to, and the third message and the first messagefurther include configuration information of the SRB.

Optionally, in another embodiment, the first message is further used toinstruct the UE to change the DRB from being associated to one basestation to being associated to another base station, and the firstmessage includes the identifier of the DRB and an identifier or index ofthe another base station to which the DRB is associated.

Optionally, in another embodiment, the base station 1100 receives afourth message from the secondary base station, for learning that thecell is added successfully, where the fourth message includes an indexof the cell of the secondary base station, and the index of the cell ofthe secondary base station is allocated by the base station 1100 and isincluded in the second message.

Optionally, in another embodiment, the base station 1100 sends anidentifier of the E-RAB and path information of the secondary basestation to a mobility management entity, so as to request the mobilitymanagement entity to instruct a serving gateway to send data of theE-RAB to the secondary base station; or, the base station 1100 forwards,to the secondary base station, the data of the E-RAB that is receivedfrom the serving gateway.

For operations and functions of the units of the base station 1100,reference may be made to the method embodiment in FIG. 1, so the detailsare not described herein again to avoid repetition.

FIG. 12 is a schematic structural diagram of a base station 1200according to another embodiment of the present invention. The basestation 1200 may be used as a primary base station for carrieraggregation. The base station 1200 includes a determining module 1210and a sending module 1220.

The determining module 1210 determines to add a DRB for a UE. Thesending module 1220 sends a fifth message to the UE, for instructing theUE to add the DRB and associate the DRB to a secondary base station,where the fifth message includes configuration information of the DRB,an identifier of the DRB, and an identifier or index of the base stationto which the DRB is associated; and the base station to which the DRB isassociated is the secondary base station.

In the embodiment of the present invention, under the control of theprimary base station of the UE, a DRB on another base station can beadded for the UE, so as to implement the carrier aggregation, therebyfurther increasing the user throughput of the UE.

Optionally, in another embodiment, before sending the fifth message tothe UE, the sending module 1220 further sends a sixth message to thesecondary base station, for requesting the secondary base station to addthe DRB for the UE, where the sixth message includes the identifier ofthe DRB and configuration information of an evolved radio access bearerE-RAB corresponding to the DRB. The base station further includes areceiving module 1230. The receiving module 1230 receives a seventhmessage from the secondary base station for responding to the sixthmessage, where the seventh message includes the configurationinformation of the DRB.

Optionally, in another embodiment, the base station 1100 sends anidentifier of the E-RAB and path information of the secondary basestation to an MME, so as to request the MME to instruct a servinggateway to send data of the E-RAB to the secondary base station; or, thebase station 1100 forwards, to the secondary base station, the data ofthe E-RAB that is received from the serving gateway.

For operations and functions of the units of the base station 1200,reference may be made to the method embodiment in FIG. 2, so the detailsare not described herein again to avoid repetition.

FIG. 13 is a schematic structural diagram of a base station 1300according to another embodiment of the present invention. The basestation 1300 may be used as a secondary base station of a UE. The basestation includes a receiving module 1310 and an addition module 1320.

The receiving module 1310 receives a second message from a primary basestation, where the second message is used to request the base station toadd a cell of the base station for a user equipment UE, and the secondmessage includes an identifier of the cell of the base station. Theaddition module 1320 adds the cell of the base station for the UEaccording to the second message.

In the embodiment of the present invention, under the control of theprimary base station of the UE, a cell of another base station can beadded for the UE, so as to implement carrier aggregation, therebyfurther increasing the user throughput of the UE.

Optionally, in another embodiment, the base station further includes asending module 1330. The sending module 1330 sends a third message tothe primary base station, where the third message is used to respond tothe second message and includes configuration information of the cell ofthe base station.

Optionally, in another embodiment, the second message is further used torequest the base station to add a data radio bearer DRB for the UE, andthe second message further includes an identifier of the DRB andconfiguration information of an evolved radio access bearer E-RABcorresponding to the DRB. The addition module 1320 is further configuredto add the DRB for the UE according to the second message.

Optionally, in another embodiment, the third message further includesconfiguration information of a signaling radio bearer SRB.

Optionally, in another embodiment, the sending module 1330 further sendsa fourth message to the primary base station for notifying the primarybase station that the cell is added successfully, where the fourthmessage includes an index of the cell of the base station, and the indexof the cell of the base station is allocated by the primary base stationand is included in the second message.

For operations and functions of the units of the base station 1300,reference may be made to the method embodiment in FIG. 3, so the detailsare not described herein again to avoid repetition.

FIG. 14 is a schematic structural diagram of a base station 1400according to another embodiment of the present invention. The basestation may be used as a secondary base station for carrier aggregation.The base station 1400 includes a receiving module 1410 and a sendingmodule 1420.

The receiving module 1410 receives a sixth message from a primary basestation, where the sixth message is used to request the base station1400 to add a DRB for a UE and includes an identifier of the DRB andconfiguration information of an E-RAB corresponding to the DRB. Thesending module 1420 sends a seventh message to the primary base station,where the seventh message is used to respond to the sixth message andincludes configuration information of the DRB

In the embodiment of the present invention, under the control of theprimary base station of the UE, a DRB on another base station can beadded for the UE, so as to implement the carrier aggregation, therebyfurther increasing the user throughput of the UE.

For operations and functions of the units of the base station 1400,reference may be made to the method embodiment in FIG. 4, so the detailsare not described herein again to avoid repetition.

FIG. 15 is a schematic structural diagram of a UE 1500 according toanother embodiment of the present invention. The UE 1500 includes areceiving module 1510 and an addition module 1520.

The receiving module 1510 receives a first message from a primary basestation, where the first message is used to instruct the UE to add acell, the first message includes configuration information of the celland an identifier or index of a base station to which the cell belongs,and the base station to which the cell belongs is a secondary basestation. The addition module 1520 adds a cell of the secondary basestation according to the first message.

In the embodiment of the present invention, under the control of theprimary base station of the UE, a cell of another base station can beadded for the UE, so as to implement carrier aggregation, therebyfurther increasing the user throughput of the UE.

Optionally, in another embodiment, the first message is further used toinstruct the UE to add a data radio bearer DRB and associate the DRB tothe secondary base station, and the first message further includes anidentifier of the DRB, configuration information of the DRB, and theidentifier or index of the base station to which the DRB is associated.The addition module 1520 is further configured to add the DRB andassociate the DRB to the secondary base station according to the firstmessage.

Optionally, in another embodiment, the receiving module 1510 receives afifth message from the primary base station, where the fifth message isused to instruct the UE to add the DRB and associate the DRB to thesecondary base station, and the fifth message includes the configurationinformation of the DRB, the identifier of the DRB, and an identifier orindex of a secondary base station setting up the DRB with the UE. Theaddition module 1520 adds the DRB and associates the DRB to thesecondary base station according to the fifth message.

According to another embodiment of the present invention, the firstmessage is further used to instruct the UE to change the DRB from beingassociated to one base station to being associated to another basestation, and the first message includes the identifier of the DRB andthe identifier or index of the base station to which the DRB isassociated. The UE further includes: a changing module 1530, configuredto change the DRB from being associated to one base station to beingassociated to another base station.

According to another embodiment of the present invention, the firstmessage is further used to instruct the UE to set up a signaling radiobearer SRB with the secondary base station, and the first messagefurther includes configuration information of the SRB. The UE furtherincludes: a setup module 1540, configured to set up the SRB with thesecondary base station according to the first message.

For operations and functions of the units of the UE 1500, reference maybe made to the method embodiment in FIG. 5, so the details are notdescribed herein again to avoid repetition.

FIG. 16 is a schematic structural diagram of a UE 1600 according toanother embodiment of the present invention. The UE 1600 includes areceiving module 1610 and an addition module 1620.

The receiving module 1610 receives a fifth message from a primary basestation, where the fifth message is used to instruct the UE to add adata radio bearer DRB and associate the DRB to a secondary base station,and the fifth message includes configuration information of the DRB, anidentifier of the DRB, an identifier or index of the base station towhich the DRB is associated. The addition module 1620 adds the DRB andassociates the DRB to the secondary base station according to the fifthmessage.

In the embodiment of the present invention, under the control of theprimary base station of the UE, an SRB on another base station can beadded for the UE, so as to implement carrier aggregation, therebyfurther increasing the user throughput of the UE.

According to another embodiment of the present invention, the receivingmodule 1610 receives data of the DRB from the secondary base station; orsends data of the DRB to the secondary base station.

For operations and functions of the units of the UE 1600, reference maybe made to the method embodiment in FIG. 6, so the details are notdescribed herein again to avoid repetition.

FIG. 17 is a schematic architecture diagram of a system according to anembodiment of the present invention.

An embodiment of the present invention provides a communication system,which includes a UE 1710, a base station 1720, and a base station 1730.The UE 1710 may be the UE 1500 in FIG. 15 or the UE 1600 in FIG. 16. Thebase station 1720 may be the base station 1100 in FIG. 11 or the basestation 1200 in FIG. 12. The base station 1730 may be the base station1300 in FIG. 13 or the base station 1400 in FIG. 14.

According to the embodiment of the present invention, a data partitionsolution based on a service (bearer) may be adopted between basestations. Specifically, a service is associated to a base station, andif a service (or an E-RAB or an RB (Radio bearer, radio bearer)) isassociated to a base station, related data of the service (E-RAB or RB)is transmitted through the base station. Referring to FIG. 17, a service1, a service 2, and a service 3 pass through a PDCP (Packet DataConvergence Protocol, packet data convergence protocol) layer, an RLC(Radio Link Control, radio link control) layer, and a MAC (Media AccessControl, media access control) layer of the base station 1720, and aretransferred through a cell 1 and a cell 2, while a service 4 and aservice 5 pass through a PDCP layer, an RLC layer, and a MAC layer ofthe base station 1730, and are transferred through a cell 3 and a cell4. According to the embodiment of the present invention, an underlyingaggregation solution which is the same as the Release-10 version of 3GPPmay be adopted in the base station.

Persons of ordinary skill in the art may appreciate that, with referenceto the examples described in the embodiments disclosed herein, units andalgorithm steps can be implemented by electronic hardware, or acombination of computer software and electronic hardware. Whether thefunctions are executed by hardware or software depends on particularapplications and design constraint conditions of the technicalsolutions. Persons skilled in the art may use different methods toimplement the described functions for each particular application, andsuch implementation shall be construed as falling within the scope ofthe present invention.

It may be clearly understood by persons skilled in the art that, for thepurpose of convenient and brief description, reference may be made tothe corresponding process in the method embodiments for a specificworking process of the foregoing systems, apparatuses, and units, so thedetails are not described herein again.

In the several embodiments provided in the present application, itshould be understood that, the disclosed system, apparatus, and methodmay be implemented in other manners. For example, the describedapparatus embodiment is merely exemplary. For example, the unit divisionis merely logical function division and may be other division in actualimplementation. For example, a plurality of units or components may becombined or integrated into another system, or some features may beignored or not performed. In addition, the shown or discussed mutualcouplings or direct couplings or communication connections may beimplemented through some interfaces. The indirect couplings orcommunication connections between the apparatuses or units may beimplemented in electronic, mechanic, or other forms.

The units described as separate parts may be or may not be physicallyseparate, and parts displayed as units may be or may not be physicalunits, which may be located in one location, or may be distributed onmultiple network elements. A part or all of the units may be selectedaccording to actual needs to achieve the objectives of the solutions ofthe embodiments.

In addition, various functional units according to each embodiment ofthe present invention may be integrated in one processing unit or mayphysically exist as separate units, or two or more units may also beintegrated in one unit.

If the function is implemented in a form of a software functional unitand sold and used as an independent product, the function may be storedin a computer readable storage medium. Based on such understanding, thetechnical solutions of the present invention essentially, or the partcontributing to the prior art, or part of the technical solutions may beimplemented in the form of a software product. The computer softwareproduct is stored in a storage medium, and includes several instructionsfor instructing a computer device (which may be a personal computer, aserver, or a network device) to perform all or a part of the steps ofthe method described in the embodiments of the present invention. Thestorage medium includes any medium that can store program codes, such asa USB flash drive, a mobile hard disk, a read-only memory (ROM,Read-only Memory), a random access memory (RAM, Random Access Memory), amagnetic disk, or an optical disk.

The foregoing description is merely specific embodiments of the presentinvention, but is not intended to limit the protection scope of thepresent invention. Any variations or replacements made by personsskilled in the art within the technical scope of the present inventionshall fall within the protection scope of the present invention.Therefore, the scope of the present invention shall be subject to theappended claims.

What is claimed is:
 1. An apparatus, comprising: at least one processorconfigured to: obtain an identifier of a data radio bearer (DRB) from aprimary base station; and associate the DRB with a secondary basestation wherein data carried on the DRB to be communicated via a cell ofthe secondary base station and between the secondary base station andthe apparatus; and a memory coupled to the at least one processor. 2.The apparatus according to claim 1, wherein the at least one processoris further configured to: obtain information of the cell of thesecondary base station; and associate the DRB with the cell of thesecondary base station.
 3. The apparatus according to claim 1, whereinthe at least one processor is further configured to: communicate withthe secondary base station, data carried on the DRB via the cell of thesecondary base station.
 4. The apparatus according to claim 1, whereinthe at least one processor is further configured to: obtain informationof a signaling radio bearer (SRB) from the primary base station; andcommunicate with the secondary base station, signaling carried on theSRB via the cell of the secondary base station.
 5. The apparatusaccording to claim 1, wherein the at least one processor is furtherconfigured to: obtain an indication from the primary base station,wherein the indication is used to instruct the at least one processor toassociate the DRB with the secondary base station.
 6. The apparatusaccording to claim 1, wherein the at least one processor is furtherconfigured to: obtain an identifier or index of the secondary basestation.
 7. The apparatus according to claim 1, wherein the at least oneprocessor is configured to: receive a signaling from the primary basestation, wherein the signaling is used to instruct the apparatus toassociate the DRB with the secondary base station.
 8. The apparatusaccording to claim 7, wherein the signaling further comprisesinformation of the cell of the secondary base station.
 9. The apparatusaccording to claim 7, wherein the signaling further comprises theidentifier of the DRB.
 10. The apparatus according to claim 7, whereinthe signaling further comprises an identifier or index of the secondarybase station.
 11. A non-transitory computer-readable storage mediumcomprising instructions, that when executed by at least one processor,cause the at least one processor to: obtain an identifier of a dataradio bearer (DRB) from a primary base station; and associate the DRBwith a secondary base station wherein data carried on the DRB to becommunicated via a cell of the secondary base station and between thesecondary base station and the at least one processor.
 12. Thenon-transitory computer-readable storage medium according to claim 11,wherein the instructions further cause the at least one processor to:obtain information of the cell of the secondary base station; andassociate the DRB with the cell of the secondary base station.
 13. Thenon-transitory computer-readable storage medium according to claim 11,wherein the instructions further cause the at least one processor to:communicate with the secondary base station, data carried on the DRB viathe cell of the secondary base station.
 14. The non-transitorycomputer-readable storage medium according to claim 11, wherein theinstructions further cause the at least one processor to: obtaininformation of a signaling radio bearer (SRB) from the primary basestation; and communicate with the secondary base station, signalingcarried on the SRB via the cell of the secondary base station.
 15. Thenon-transitory computer-readable storage medium according to claim 11,wherein the instructions further cause the at least one processor to:obtain an indication from the primary base station, wherein theindication is used to instruct the at least one processor to associatethe DRB with the secondary base station.
 16. The non-transitorycomputer-readable storage medium according to claim 11, wherein theinstructions further cause the at least one processor to: obtain anidentifier or index of the secondary base station.